The 3503 produces 70hp at 6500 rpm while building an impressive torque of 57 ft lbs. at 6000 rpm. Operating in an Rpm range 1500 Rpm higher than the 60Hp 3502 results in much more thrust at full power for vehicles requiring more climb capability than cruise power as the 3502 is designed for. Fuel rate is 30-40% less than competing brands of 2 cycle engines in the same Hp range.

3503 incorporates Al-Nikasil coated cylinders for superior performance and reliability. Al-Nikasil in simple terms is a nickel based material, applied in a paste form, when super heated it becomes part of the cylinder itself. Al-Nikasil provides for a super low coefficient of friction, reducing engine heat and wear. The combination of Nikasil cylinders with water cooling render these engines immune from cold seizure, shock cooling or seizure from high EGT conditions. The pistons and cylinders expand at the same rate thus providing for a seizure resistant environment. 3503 crankshaft is 4130 chrome molly steel. Heads, cylinders, rings, block casting, connecting rods and associated components are all of the highest grade alloys available. With optional vertically mounted fuel injection 3502/03 can be used in compact engine compartments. Mounting bolt pattern is identical to the R-582.